1. Field of the Invention
The present invention relates to a substrate processing apparatus for processing substrates such as a semiconductor substrate and a glass substrate.
2. Description of the Prior Art
Conventionally, when a substrate as a processing target is not present in a substrate processing apparatus (for example, after a substrate processing is completed), a process chamber remains in a non-operational state. After a next substrate to be processed is loaded into the substrate processing apparatus, the substrate is heat-treated if necessary.
However, if an interval between production processes increases, a temperature inside of the process chamber decreases excessively, which causes a difference between the initial processing result of a processed substrate and the processing result of a successively processed substrate. Furthermore, organic materials attached to the inside of a process chamber or a boat installed in a transfer chamber, leading to the quality degradation.